The present application is related to U.S. Ser. No. 08/022,107, and U.S. Ser. No. 08/022,108 filed on Feb. 25, 1993.
The present invention relates to a manual transmission of a motor vehicle, comprising a plurality of forward gears, which can be shifted via synchronizer clutches, and one reverse gear.
In the book "Mechanical Transmissions", by Johannes Loomann, Springer-Verlag Berlin, 1988, Page 10, auxiliary transmissions are described which represent a normally two-speed range transmission which is connected in front of or behind the normal manual transmission. They have the purpose of increasing the number of gears and the gearing range of the transmission by the multiple utilization of the gearwheel sets. It is stated there that, in the case of an interaction with an auxiliary transmission, the gearing ratios .phi. in all steps must be approximately identical; that is, they must form a geometrical row in order to avoid irregularly alternating large and small gearing ratios.
It is an object of the invention to provide a manual transmission comprising an auxiliary transmission which, deviating from the geometrical grading, results in a gear grading .phi. which increases in the direction of the lower gears.
This and other objects are achieved by the present invention which provides a manual transmission of a motor vehicle, comprising transmission gears that include a plurality of forward gears and one reverse gear, synchronizer clutches which shift the gears, with all of the transmission gears being arranged such that they can be shifted only by simultaneous closing of two of the synchronizer clutches which are assigned to each gear. The transmission gears are arranged such that a progressive gear grading is provided, with a first range shifting implemented between adjacent transmission gears and a second range shifting implemented between non-adjacent transmission gears.
When a first range shifting is implemented between adjacent gears G1 and G2 and a second range shifting is implemented between the non-adjacent gears G3 and G5, a progressive grading can be achieved which rises in the direction of the lower gears, without the occurrence of irregularly alternating gearing ratios. This progressive grading is desirable in order to achieve a larger spread in the lower gears.
In an embodiment of the invention, for a 6-gear transmission, gears G2, G4, G5 and G6 each have a fixed-wheel loose-wheel gearwheel pair. The first gear G1 is formed by the gearwheel pair of G2 and the gears G4 and G6 which are connected behind it as an auxiliary transmission. The third gear G3 is formed by the gearwheel pair of G5 and the gears G4 and G6 which are connected as an auxiliary transmission. Since the gearwheel pairs of G4 and G6, which already exist in the manual transmission, are used as the auxiliary gears, additional gearwheel pairs are not required so that the manufacturing costs and the installation space of the transmission may be kept very low.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.